192 THE POTATO 



therefore, that farmers are led to believe that their 

 potatoes are affected with early blight and other 

 diseases when the trouble has been brought on by 

 themselves through the improper use of Paris green. 

 Injuries resulting from the use of this substance 

 are very apt to occur where flea beetles have eaten 

 the foliage. The arsenic attacks the tissues at such 

 points, and as a result more or less circular brown 

 spots are produced, having for their centres the 

 holes eaten out by the flea beetles. By combining 

 the Paris green with Bordeaux mixture, as already 

 described, these injuries may be wholly avoided. 

 "The cost of the work of spraying, as described 

 here will depend to a considerable extent upon 

 the kind of machinery used and the price paid for 

 labor. With suitable apparatus, and labor at 

 $1.50 per day, potatoes maybe sprayed six times 

 for about $6 per acre. This estimate is based 

 upon experiments extending over several years, 

 and includes the cost of chemicals as well as labor. 

 The cost of treating scab is mainly in the labor 

 involved in dipping and drying the seed, and sel- 

 dom exceeds 15 cents per acre. Much atten- 

 tion has been given to the effects of Bordeaux 

 mixture on the growth and yield of potatoes aside 

 from its value in keeping parasitic foes in check. 

 It has been shown conclusively that it pays to 

 apply this preparation if for no other purpose than 

 to induce a more vigorous growth. Three or four 

 applications of the mixture have in many cases 

 increased the yield of potatoes 50 per cent., so that 

 no matter where the crop is grown, or whether 

 diseases are present or not, the writer feels war- 

 ranted in recommending the application of the 

 mixture, on the ground that its use will yield a 

 handsome return," 



